Motion Hourglass

Demonstration of several MotionLayout concepts and features working together:

• Each ConstraintSet denotes the various states of the hourglass while keeping the vertical or horizontal chain packed.
• Some Constraints are specifying a pathMotionArc to get the curved path of motion.
• ImageFilterView is used with a CustomAttribute property transition on crossfade to change how the sand appears.
• A simple rotation transformation keeps both the glass and sand rotating along their respective paths.
• The sand is constrainted by the glass
• KeyFrameSets adjust for alpha and rotation quirks to keep the ends of the animation from glitching
• autoTransition starts the animation and keeps it going forever